On Sat, 3 Nov 2012 06:56:36 -0700 (PDT),
wrote:

My parents have electricity but their cable/phone/internet is out and they can still watch their (Optimum) DVR.

I don't know why you can't hook up a giant battery to the fios system and maybe your own charger and disconnect their charger but their tech told me specifically that a bigger battery wouldn't work with their little charging system. I suppose you could keep a car or marine battery separately charged and just hook it up when you need to.

Also, I was told that when the power goes out it shuts off TV and internet to make the battery last longer for the more-important phone service (or maybe TV/internet use so much more power they'd drain the battery really fast).

And a lot of people forget that their cordless phones won't work without AC because the base unit needs it (although some systems allow for batteries in the base unit too).

Monday night, I had 21 power failures of one second each. And yeah,
the cordless phone kept hanging up on my phone call. After 3 times I
went to the corded phone. Every time the power came back on, the 15
year old 14" color tv would make a noise, a very short growl, even
though it was off before the outage and stayed off after the power
came back.